Variable face cam



April 27, 1943. H. DEVLIN VARIABLE FACE CAM Filed June 9, 1941 2Sheets-Sheet 1 A ia! 27, 1943. H. DEVLIN VARIABLE FACE CAM Filed June 9,1941 2 Sheets-Sheet 2 HENRY Dam/N I NVENTOR I Patented Apr. 27, 1943VARIABLE FACE CAM Henry Devlin, Saginaw, Mich, assignor to Baker PerkinsInc., Saginaw, Mich, a corporation of New York Application June 9, 1941,Serial No. 397,278

2 Claims.

This invention relates to variable cams in which a cam follower isselectively directed through alternative cam tracks to impart variablemotion to mechanism driven by the cam follower, and has for its objectthe provision of a continuously driven face cam having communicatingcircular and eccentric tracks, together with switch mechanism fordirecting the cam follower selectively into one track or the other. Theswitch mechanism of my novel cam is actuated during rotation of the camby engaging a movable abutment member, which member is selectively movedto or from switch-changing position by any suitable part of the machinewith which the cam action is to be co-ordinated. This improved cam hasthe advantage over drum cams heretofore employed for this generalpurpose that it occupies no more space than a conventional cam, and maybe installed in many existing machines having fixed cams with little orno alteration of the machine. Where a drum cam is used the machine frameand drive mechanism ordinarily must be designed especially toaccommodate it.

An application of the cam of this invention to a specific machine isdescribed and illustrated in my copending application for improvementsin dough dividers, Serial No. 346,176, filed July 18, 1940, of whichthis present application is a continuation-in-part.

A cam embodying the features of the invention is illustrated in theaccompanying drawings, showing the switching mechanism in diiferentpositions, in which Fig. 1 shows one form of the cam and its followermechanism, the cam follower leaving the inner eccentric cam track;

Fig. 2 shows the follower in the outer circular track about to beintercepted and directed into the inner track; and

Fig. 3 shows a modified cam also embodying the invention having itseccentric track outside of its circular idling track.

Referring to Figures 1 and 2!, a cam 28, which rotatescounter-clockwise, has a circular outer track 35 and an eccentric innertrack 36. Track 36 communicates at both ends with track 35. A cam roller2! journaled on a rocker-arm 26 rides in the tracks and is actuated bythe eccentric track to rock a lever arm 25 of an associated mechanismfor any desired purpose, in known manner. The lever arm is actuated atdesired periods by the operation of the switch mechanism to direct thecam roller 21 through the eccentric track 36. When the switch mechanismdirects the cam roller through the circular track 35, the

lever arm remains at rest, though the cam continues to rotate.

The construction and operation of the switch mechanism is as follows:

Two switch points 37, 38 are pivoted on. the cam at opposite ends oftrack 36. When point 31 directs the cam follower 2! into the innertrack, the driven lever 25 is rocked to the right, then to the left asthe follower leaves track 36. The switch points 37, 38 are fastened topins 39 and 40, respectively, passing through and journaled in the bodyof the cam 26. Levers 4| and 42 are fixed to pins 39, 40, respectively,and are interconnected by mechanism for moving the points, which is nextdescribed.

For purposes of clarity, in Figs. 1 and 2, the cam body is shown inbroken lines, the levers 4|, 42, and the switching mechanism being drawnsolid, whereas actually the levers are on the opposite face of the camfrom the switch points and the cam tracks. Lever 41 of switch point 31has pivoted to it a rod 43, which passes through the eye of a guide 44fixed to the cam body. Rod 43 extends slidably through a bushing orsleeve 45 which is pivoted to the end of lever 42 of switch point 38.Beyond the sleeve a collar 46 presents an internal shoulder 41 whichengages a shoulder on the rod 43. Collar 46 is slidable upon the reducedend portion of the rod and is urged yieldingly inward by a spring 48bearing against a washer at the end of the rod.

A latch 49 is pivoted on the cam body, a spring 50 urges the latchnormally into engagement with the collar 46, and a roller 5| on thelatch is positioned to engage a movable abutment member 53 duringrotation of the cam and reelase the latch.

Fig. 2 shows the switch point 31 open to pick up the cam roller 21 anddirect it into the inner track 36. The latch 49 is released, and collar46, lever 42, rod 43, and lever 41 have been moved to the left by thepressure of springs 48 and 52.

Fig. 1 shows the roller 21 leaving the inner cam track 36. As the camrotates counter-clockwise the roller 2'! opens switch point 38, movingthe switch lever 42 and sleeve 45 down against collar 46. Thiscompresses spring 48 and urges the cam 43 down, drawing the switch point3'! closed and compressing the other spring 52. The spring latch 49engages the shoulder of collar 46 and holds switch point 31' closed. Thecam roller 21 will therefore follow the circular track 35 and willimpart no motion to the knife lever 25 until such time as point 31 isagain opened and the roller re-enters the eccentric track 36. On thenext revolution of the cam, the follower 27 engages the back of switchpoint 38 and closes it, sleeve 45 sliding up rod 43. On subsequentrotations of the cam the outer track 35 is unobstructed and operation isnoiseless.

To trip the latch 49 and switch the follower 2'! into the inner track36, an abutment lever arm 53 is fixed to a machine shaft operable tomove the arm into the position shown in Fig. 2 whenever operation oflevers 23 and 25 is desired. In this position it lies in the path oftravel of the roller 5| on the latch 49. When roller 54 engages it thelatch is moved to release collar 46. The springs 48 and 52 then move therod 43, collar 46, and switch lever arm Al downward in Fig. 2, openingthe switch 37. llhe cam follower 21 will then be directed into the innertrack 36.

As the main shaft 23 rotates counter-clockwise the cam follower passesinto the outer track (see Fig. 1) forcing the switch point 33 open. Theswitch lever 42 and its sleeve 45 move along rod 43, urging the collar56 into a position where it will be re-engaged by the spring latch 39.Through spring 48 the rod 43' is urged endwise and closes the otherswitch point 3?. This. operation will be repeated each revolution of thecam so long as the abutment-engaging means 53 remains in the path of thelatch abutment Si, or if the abutment-engaging means be moved out of thepath of latch roller 5!, the cam follower 21 will be directed into thecircular track 35, where it will ride idle as described in the secondparagraph above.

Certain details of construction in the mechanism as shown and describedmay be altered without departing from the invention as claimed herein.If desired, the circular idling track may be made smaller than theeccentric track and located within it, requiring only that the directionof swing of the switch points and the arrangement of their actuatingmechanism be changed, without altering the: essential operation of theinvention.

An embodiment of the invention, so modified, is illustrated in Fig. 3 inwhich elements identical with those of the cam above described are givenlike reference numerals. cular idler track 55 with an eccentric track 53The cam 23a has aciroutside of it. The camv roller 27 on rocker 26follows the tracks and is actuated by the eccentric track to rock thelever arm 25-. The switch points 57 and 58 are mounted at the ends ofthe eccentric track 56 on pins 59. and 85 respectively. The pins arejournaled in and extend through the body of cam 25a. When the camrotates counter-clockwise, as indicated by the arrow, the switch point5'! directs the follower alternatively into track 55 or track 55.

The mechanism for actuating and controlling the switch points, mountedon the opposite side of the cam, is shown in broken lines. Levers El,

152 are fixed to pins 58 and 60, respectively. Le-

ver 6i has pivoted to it a rod 63 slidable in a guide 64 fixed to thecam. Rod- 53 is slida'lole also in a bushing 65 pivoted to the end ofswitch lever '62. A collar 6% bearing against a shoulder (not shown) onrod 63 is slidable on the reduced end portion of 63 and is urged to theleft by coil spring 68 which bears against a stop washer at the end ofthe rod. A second spring 69 bears against guide 64 and the socket whichpivotall-y connects rod 63 to lever 6!.

A latch assembly comprising a latch 59 pivoted to the cam, a spring 50,and a roller 5|, is constructed and operates like the latch assembly inFigs. 1 and 2. The roller 51 is positioned to engage the movableabutment member 53 on the associated machine and urge the latch out ofengagement with the collar 66.

The operation is as follows: the points as shown in solid lines arepositioned to direct the follower 21 through eccentric track 56 to rockthe lever arm 25, the abutment lever 53 being in position to contact thelatch roller 5|. As the cam revolves the follower 21 will engage theoutside of switch point 58, to close it across the idler track 55 in theposition shown in dotted lines. This action will move lever 62 to theright into the position indicated in dotted lines, carrying the collar66 to the right into engagement ith the latch, compressing spring 68,and drawing rod 63 to the right. This in turn will rock lever 6|clockwise and open switch point 51, as indicated by dotted lines. Onthenext and subsequent revolutions of the cam the follower 21 willfollow the circular idler track 55, opening point 58, which can be movedfreely indirection by reason of its lost motion connection with rod 63.The follower will continue to travel in this path unless and until theabutment member 53 is moved into position to trip the latch again.

Having described the construction and operation of the foregoingembodiment of my invention, what I claim and desire to secure by LettersPatent is:

1. Inv a face cam, a circular idler track, an eccentric. track openingat its ends into said circular track, a switch. point at each end ofsaid eccentric track between it and said idler track, pivotally mountedso that a cam follower can be selectively directed during rotation ofthe cam to pass either through said eccentric track or said idler track,a connection between said switch points operable to close the leadingswitch point in response to displacement of the rearward switch point bythe cam follower passing out of the eccentric track toclose the leadingswitch point across said eccentric track, resilient means normallyurging said leading switch point open across said idler track to directthe cam follower into said eccentric track, and spring latch meansarranged normally to retain said leading switch point closed across saideccentric track, and an abutment on said latch means for engagement withabutment-engaging means movable to and away from the path of travel ofsaid latch abutment during rotation of the. cam, said latch abutmentoperable on engagement with said abutment-engaging means to release saidlatch means to permit the leading switchpoint. to close off the idlertrack and open the eccentric track to direct the cam follower thereinto.

2. The combination claimed in claim wherein the. rearward switch pointhas a: lost-motion connection with. the leading switch point, so thatits motion. is effective only to. close. t'ncleading switch point acrossthe eccentricv track, its movement. in the opposite direction in nowiseaffecting. the situation of the leading. point.

DEIVLIN

